Together with Anopheles gambiae and An. arabiensis, An. funestus is among the most important malaria vectors in the world. With sporozoite rates as high as 9 percent in parts of Africa, it is clear that An. funestus cannot be ignored in any comprehensive plan to control or eradicate malaria from this continent. Whatever control strategy is implemented against An. gambiae s.l. must be integrated with control against An. funestus. Because it is currently impossible to maintain colonies of An. funestus in the laboratory, neither classical genetic control schemes nor transgenic strategies can be developed. However, the importance of a detailed understanding of vector population structure transcends genetic control programs, as this knowledge is also pivotal to the successful use of insecticides in vector control, given limited financial and human resources. This knowledge allows predictions to be made about the response of vector populations to human interventions or genetic changes, e.g., the potential for spread of mutations conferring insecticide resistance. Unfortunately, the population genetics structure of An. funestus is poorly understood and relatively unstudied to date. Very few molecular genetic markers have been developed for this species. The experiments outlined in this proposal will employ cytogenetically mapped molecular markers that we have developed to address fundamental questions about gene flow within and between An. funestus populations. What is the size of a deme and what is the effect of distance and habitat on gene flow between demes? Are carries of alternative chromosomal inversion arrangements reproductively isolated? Do they have epidemiologically relevant differences in biting and resting behavior? Information gained from the use of these markers will enable us to more efficiently manage the currently available tools for vector control and will lay the necessary foundation if genetis strategies against An. funestus become possible